Safety and tolerance of three probiotic strains in healthy infants: a multi-centre randomized, double-blind, placebo-controlled trial.

Some strains of species belonging to the genera Bifidobacterium and Lactobacillus are used in order to maintain health. Although these organisms have a long record of safe use, it is important to assess their safety and tolerance in potentially vulnerable populations, such as infants. The objective of this study was to evaluate the safety and tolerance of three probiotic strains (Bifidobacterium longum subsp. infantis R0033, Bifidobacterium bifidum R0071 and Lactobacillus helveticus R0052) in healthy infants aged 3 to 12 months. A multi-centre randomized, double-blind, placebo-controlled intervention study with 221 healthy full-term infants was conducted. Infants received either a placebo or one of the 3 probiotic strains (3×10 cfu) daily during an 8 week intervention period. Growth (weight, height and head circumference), adverse events (AEs)/serious adverse events (SAEs), concentrations of D-lactic acid in urine samples, characteristics of the stools and use of medication were collected for safety evaluation. All 4 groups were homogeneous with respect to age, gender, feeding type, ethnicity, height, weight and head circumference at the start of the study. The results showed that changes in growth (weight, height and head circumference) were equivalent in all 4 groups. No SAEs were reported. Total number of AEs recorded was equivalent in all groups. Thus, the use of B. infantis R0033, L. helveticus R0052 and B. bifidum R0071 in infancy is safe, and well tolerated.